JP2016210080A - Molding and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a bond strength between both of a first member formed of a fiber-reinforced resin and a second member formed of a material containing a thermoplastic resin in a molding in which the first member and the second member are bonded to each other.SOLUTION: A method for producing a molding includes: a surface working step of heating a surface of a first member 4 containing a resin 2 and a reinforcing fiber 1 to a melting point of the resin 2 or higher or a glass transition point or higher, and thereby working the surface into an uneven shape; and a bonding step of injection molding a material (D) containing a thermoplastic resin (C) onto the worked surface of which the surface temperature is a melting point of the resin 2 or higher or the glass transition point or higher.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method of manufacturing a molded body by injection molding a material containing a thermoplastic resin on a member made of fiber reinforced resin, and a molded body manufactured by the method.

  Fiber reinforced composite materials containing reinforced fibers and thermoplastic resins are widely used in various industrial applications because of their excellent light weight and mechanical properties. As a method for producing a molded body partially using a fiber reinforced composite material, for example, a method in which a thermoplastic resin is injection-molded and integrated on a member made of a fiber reinforced composite material is used.

In Patent Document 1, in order to improve the bonding strength between a member made of a fiber reinforced composite material and a member injection-molded thereon, one of the front and back surfaces of a nonwoven fabric made of reinforced fibers is used as the fiber reinforced composite material. A method of manufacturing a molded body using a fiber reinforced resin sheet in which the surface is impregnated with a thermoplastic resin and the reinforcing fiber is exposed on the other surface is described.
In this method, first, a nonwoven fabric composed of reinforcing fibers and a resin sheet composed of a first thermoplastic resin were laminated in the order of resin sheet / nonwoven fabric / resin sheet / nonwoven fabric / resin sheet / nonwoven fabric / nonwoven fabric and heated and pressurized. By cooling later, a laminated integrated product (fiber reinforced resin sheet) in which the reinforcing fibers are exposed on one surface is produced. Next, the fiber reinforced resin sheet is placed in a mold, a second thermoplastic resin is injection-molded on the surface where the fiber is exposed, and a molded product of the fiber reinforced resin sheet and the second thermoplastic resin are molded. To obtain a molded product integrated with the molded product.
According to this method, since the fiber exposed on one surface of the fiber reinforced resin sheet is solidified in the state impregnated with the second thermoplastic resin, an anchoring effect by the fiber is obtained, and the joint strength between the two molded products is obtained. Is stated to improve.

JP 2014-172201 A

However, even in the molded article obtained by the method described in Patent Document 1, it cannot be said that the bonding strength between the molded article of the fiber reinforced resin sheet and the molded article of the second thermoplastic resin is sufficient. It is desired to further improve the bonding strength.
The present invention provides a method for producing a molded body capable of improving the bonding strength of both members in a molded body in which a first member made of a fiber reinforced resin and a second member made of a material containing a thermoplastic resin are joined, And a molded article produced by the method.

The present invention has the following configuration.
[1] A molded body in which a first member containing a resin (A) and a reinforcing fiber (B) and a second member made of a material (D) containing a thermoplastic resin (C) are joined is manufactured. It is a method, Comprising: The surface of the 1st member containing resin (A) and a reinforced fiber (B) is heated more than melting | fusing point or glass transition point of resin (A), and this surface is made uneven | corrugated. A surface processing step of processing or performing processing of exposing the reinforcing fibers (B) on the surface; and a thermoplastic resin on the processed surface having a surface temperature equal to or higher than a melting point of the resin (A) or a glass transition point The manufacturing method of a molded object which has a joining process which injection-molds the material (D) containing (C).

  [2] A molded body in which the first member containing the resin (A) and the reinforcing fiber (B) and the second member made of the material (D) containing the thermoplastic resin (C) are joined is manufactured. It is a method, and the surface of the first member containing the resin (A) and the reinforcing fiber (B) is heated to a temperature equal to or higher than the decomposition temperature of the resin (A), so that the surface is processed into an uneven shape, or A thermoplastic resin (C) is formed on the processed surface having a surface processing step for exposing the reinforcing fibers (B) on the surface and having a surface temperature equal to or higher than the melting point of the resin (A) or the glass transition point. The manufacturing method of a molded object which has the joining process of injection-molding the material (D) containing.

[3] The method for producing a molded body according to [1] or [2], wherein, in the surface processing step, the surface of the first member is heated with an infrared heater.
[4] The method for manufacturing a molded body according to [1] or [2], wherein, in the surface processing step, the surface of the first member is irradiated with a laser beam.
[5] The method for producing a molded body according to any one of [1] to [4], wherein the material (D) containing the thermoplastic resin (C) further contains reinforcing fibers.
[6] A molded body produced by the method for producing a molded body according to any one of [1] to [5], wherein the maximum height on the surface of the first member is 1 to 45 μm.

According to the method for producing a molded article of the present invention, a first member containing a resin (A) and a reinforcing fiber (B), and a second member made of a material (D) containing a thermoplastic resin (C); It is possible to improve the bonding strength between the first member and the second member in the molded body in which is bonded.
According to the present invention, the first member containing the resin (A) and the reinforcing fiber (B) and the second member made of the material (D) containing the thermoplastic resin (C) have high bonding strength. A joined molded body is obtained.

It is sectional drawing which shows typically the example of the 1st member before a surface processing process. It is sectional drawing which shows typically the example of the 1st member after a surface processing process. It is sectional drawing which shows typically the example of the 1st member after a surface processing process. It is sectional drawing which shows typically the example of the 1st member after a surface processing process. It is sectional drawing which shows typically the example of the 1st member before a surface processing process. It is sectional drawing which shows typically the example of the 1st member after a surface processing process. It is sectional drawing which shows typically the example of the 1st member after a surface processing process. It is the schematic for demonstrating the surface processing process in a test example. It is the schematic for demonstrating the joining process in a test example. It is the schematic for demonstrating the surface processing process in an Example. It is the schematic for demonstrating the joining process in an Example. It is a perspective view of the molded object obtained in the Example. It is the schematic for demonstrating the surface processing process in an Example.

<First member>
A 1st member consists of fiber reinforced resin containing resin (A) and a reinforced fiber (B). Examples thereof include a prepreg obtained by impregnating a resin (A) on a base material composed of reinforcing fibers (B), a prepreg laminate in which a plurality of prepregs are laminated, or a member obtained by molding these. Moreover, the member shape | molded using the pellet which knead-dispersed discontinuous fiber in resin may be sufficient.

The type of the reinforcing fiber (B) is not particularly limited, and for example, reinforcing fibers having inorganic fibers, organic fibers, metal fibers, or a hybrid structure in which these are combined can be used.
Examples of the inorganic fiber include carbon fiber, graphite fiber, silicon carbide fiber, alumina fiber, tungsten carbide fiber, boron fiber, and glass fiber. Examples of the organic fibers include aramid fibers, high density polyethylene fibers, other general nylon fibers, and polyester fibers. Examples of metal fibers include fibers such as stainless steel and iron, and carbon fibers coated with metal may be used. Of these, carbon fibers are preferred in view of mechanical properties such as strength of the molded body.

The average fiber diameter of the reinforcing fibers (B) is preferably 1 μm or more, and more preferably 5 μm or more. It is preferable that the average fiber diameter of the reinforcing fibers (B) is 1 μm or more because the handling properties of the reinforcing fibers (B) are improved and the impregnation property of the resin is improved. The upper limit of the average fiber diameter of the reinforcing fibers (B) is not particularly limited, but is preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less in terms of manufacturability or cost.
The reinforcing fiber (B) may be a continuous fiber or a discontinuous fiber.
Excellent mechanical properties such as rigidity and strength of the molded product obtained by using continuous fibers.
On the other hand, discontinuous fibers are easy to obtain good fluidity of the fiber reinforced resin, and are excellent in formability. When the reinforcing fiber (B) is a discontinuous fiber, the discontinuous fiber in the first member may keep the shape of the bundle, may be in a monofilament state, or both the bundle and the monofilament may be mixed.

As a form of the substrate composed of continuous fibers which are the reinforcing fibers (B), a form in which a large number of continuous fibers are aligned in one direction to form a UD sheet (unidirectional sheet), or a cloth material by weaving continuous fibers (woven fabric) ) Is preferred. Examples of the cloth weaving method include plain weave, twill weave, satin weave, and triaxial weave.
The UD sheet (unidirectional sheet) may be used as a single layer or may be laminated in multiple layers. When laminating, the directions of the reinforcing fibers in each layer may be the same or may be laminated at an arbitrary angle. For example, the alternating orthogonal lamination which laminated | stacked alternately so that the direction of a reinforced fiber might be 0 degree and 90 degrees is mentioned.

As a form of a base material composed of discontinuous fibers which are reinforcing fibers (B), an anchoring structure with a material (D) injected in a joining step described later is easily formed, and the first member and the second member A reinforcing fiber web in which chopped reinforcing fiber bundles are dispersed is preferable in that it is easy to obtain a strong joint. Examples of a method for producing such a reinforcing fiber web include a method of dispersing a chopped reinforcing fiber bundle in a liquid, a method of dispersing in a gas phase, or a method using a machine such as carding or needle punch.
In the method of dispersing the reinforcing fiber bundle in the liquid, the fiber bundle chopped in the liquid (water or the like) is supplied, dispersed while loosening the fiber bundle, and slurried. Thereafter, the reinforcing fiber web is obtained by dehydration and drying. If necessary, the liquid to be dispersed may contain a binder resin or a surfactant. By using a binder resin or a surfactant, the handleability of the reinforcing fiber web can be improved.
Examples of the method of dispersing the reinforcing fiber bundle in the gas phase include a method of blowing a gas such as air or nitrogen to the chopped reinforcing fiber bundle.

Or the nonwoven fabric in which a monofilament is disperse | distributed is preferable as a form of the base material which consists of a discontinuous fiber which is a reinforced fiber (B).
When discontinuous fibers are dispersed in a monofilament state in the first member, an anchoring structure with the material (D) injected in the joining process described later is more easily formed than in the case of the above-described reinforcing fiber web. Therefore, it is preferable in that a strong joint between the first member and the second member is easily obtained.

The weight average fiber length of the discontinuous fibers that are the reinforcing fibers (B) is preferably 1 mm or more. When the weight average fiber length of the reinforcing fibers is 1 mm or more, the effect of improving the strength and rigidity of the first member or the molded body provided with the first member is sufficiently obtained. The upper limit of the weight average fiber length of the reinforcing fiber (B) is preferably 100 mm or less in terms of fluidity in the mold and mold followability.
The discontinuous fiber has a weight average fiber length of more preferably 2 to 80 mm, further preferably 3 to 60 mm.

The resin (A) may be a thermoplastic resin or a thermosetting resin.
Examples of the thermoplastic resin that is the resin (A) include polyamide resins (nylon 6, nylon 66, aromatic nylon, etc.), polyolefin resins (polyethylene, polypropylene, etc.), modified polyolefin resins (modified polypropylene resin, etc.), polyester resins (polyethylene). Terephthalate, polybutylene terephthalate, etc.), polycarbonate resin, polyamideimide resin, polyphenylene oxide resin, polysulfone resin, polyethersulfone resin, polyetherketone resin, polyetherimide resin, polystyrene resin, ABS resin, polyphenylene sulfide resin, liquid crystal polyester resin And a copolymer of acrylonitrile and styrene, a copolymer of nylon 6 and nylon 66, and the like.
Examples of the modified polyolefin resin include acid-modified polyolefin resins (acid-modified polypropylene resins and the like) obtained by modifying a polyolefin resin with an acid such as maleic acid.
As resin (A), 1 type may be used independently and 2 or more types may be used together.
In particular, in terms of moldability, it is preferable to include one or more selected from the group consisting of polypropylene resins, acid-modified polypropylene resins, polyamide resins, and polyester resins. Moreover, it is preferable that 1 or more types chosen from the group which consists of a polyphenylene sulfide resin, a polycarbonate resin, a polyether ketone resin, and a polyetherimide resin is included at the point of mechanical physical property and heat resistance.

  When the resin (A) is a thermosetting resin, it preferably contains one or more selected from the group consisting of epoxy resins, vinyl ester resins, and unsaturated polyester resins.

The first member is a flame retardant, weather resistance improver, antioxidant, thermal stabilizer, ultraviolet absorber, plasticizer, lubricant, colorant, compatibilizer, conductive, depending on the required properties of the desired molded article. You may contain additives, such as a property filler.
The fiber volume content (Vf) of the first member is preferably 5 to 60%, more preferably 10 to 55%, and still more preferably 15 to 50%. The strength and rigidity of the first member are high when it is at least the lower limit of the above range, and the impregnation property of the resin (A) to the reinforcing fibers (B) is good when it is at most the upper limit.
In the present specification, the fiber volume content (Vf) is a value obtained by a measurement method based on JIS K7075.

<Second member>
The second member is made of a material (D) containing a thermoplastic resin (C).
It does not specifically limit as a thermoplastic resin (C), For example, the same thing as the thermoplastic resin which is resin (A) is mentioned. As a thermoplastic resin (C), 1 type may be used independently and 2 or more types may be used together.
In particular, in terms of moldability, it is preferable to include one or more selected from the group consisting of polypropylene resins, acid-modified polypropylene resins, polyamide resins, and polyester resins. Moreover, it is preferable that 1 or more types chosen from the group which consists of a polyphenylene sulfide resin, a polycarbonate resin, a polyether ketone resin, and a polyetherimide resin is included at the point of mechanical physical property and heat resistance.
It is preferable that the resin (A) of the first member and the thermoplastic resin (C) of the second member to be bonded to each other are the same type of resin, because the bonding strength between both members tends to be high.

Material (D) may contain reinforcing fibers. When the reinforcing fiber is contained in the material (D), the mechanical properties such as rigidity and strength of the second member are improved, and thus the physical properties of the molded body in which the first member and the second member are joined are also improved. Can do. The kind of the reinforcing fiber to be contained in the material (D) is the same as that of the reinforcing fiber (B) and the preferred embodiment.
The average fiber diameter and fiber length of the reinforcing fibers contained in the material (D) before injection can be set within a range where the material (D) can be injection molded.
The weight average fiber length of the reinforcing fibers in the material (D) before injection is preferably 1 mm or more, more preferably 1.3 mm or more, and more preferably 1.5 mm or more in that the effect of improving mechanical properties can be sufficiently obtained. Further preferred. The upper limit is preferably 25 mm or less, more preferably 20 mm or less, and even more preferably 15 mm or less in terms of fluidity of the material (D) and mold followability.
By injection-molding the material (D), the length of the reinforcing fibers included is shortened. The weight average fiber length in the second member is preferably 0.1 mm or more, more preferably 0.2 mm or more, and further preferably 0.3 mm or more in that the effect of improving the mechanical properties can be sufficiently obtained. The upper limit is preferably 15 mm or less, more preferably 10 mm or less, and even more preferably 5 mm or less from the viewpoint of dispersibility of the reinforcing fibers in the material (D).
The average fiber diameter of the reinforcing fibers in the material (D) is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more from the viewpoint that the remaining fiber length after injection tends to be long. The upper limit is preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less from the viewpoint of injection moldability.
Material (D) is a flame retardant, a weather resistance improver, an antioxidant, a heat stabilizer, an ultraviolet absorber, a plasticizer, a lubricant, a colorant, a compatibilizer, a conductive material, depending on the required properties of the target molded article. You may contain additives, such as a property filler.
The fiber volume content (Vf) when the second member includes reinforcing fibers is preferably 5 to 60%, more preferably 10 to 55%, and still more preferably 15 to 50%. When it is at least the lower limit of the above range, the strength and rigidity of the material (D) are high, and when it is at most the upper limit, the dispersibility of the reinforcing fibers in the material (D) is good.

<Method for producing molded body>
The method for producing a molded body of the present invention includes a surface processing step of heating the surface of the first member to process it into irregularities, or performing processing to expose the reinforcing fibers (B) on the surface, and the processed surface There is a joining step of injection molding the material (D) containing the thermoplastic resin (C).

[Surface machining process]
(First aspect)
In the first aspect of the surface processing step, the surface of the first member is heated to the melting point of the resin (A) or higher or the glass transition point or higher.
The heating means is not particularly limited, and examples include an infrared heater, a plate heater, a hot air heater, an energizing heating device, and a laser irradiation device. Among these, an infrared heater or a laser irradiation apparatus is preferable.
An infrared heater is preferable in that it can be heated uniformly without contact. As the type of infrared heater, a far infrared heater is preferable when importance is attached to heating uniformity, and a near infrared heater is preferable when importance is placed on short time heating.
Laser light irradiation is preferable in that it can be locally heated. As the type of laser light, a gas laser such as a carbon dioxide laser or an excimer laser, a solid laser such as a YAG laser or a YVO ₄ laser, and a fiber laser can be used.

The heating temperature for heating the surface of the first member is set so that the surface temperature of the heated region is equal to or higher than the melting point (Tm ° C.) of the resin (A). The surface temperature is preferably Tm + 10 ° C. or higher, and more preferably Tm + 20 ° C. or higher in that the surface of the first member can be easily processed.
The heating temperature when the resin (A) does not have a melting point is set so that the surface temperature of the heated region is equal to or higher than the glass transition temperature (Tg ° C.) of the resin (A). The surface temperature is preferably Tg + 10 ° C. or higher, more preferably Tg + 20 ° C. or higher, in that the surface of the first member can be easily processed.
In this aspect, the upper limit of the surface temperature of the heated region of the first member is lower than the decomposition temperature of the resin (A).
The melting point, glass transition temperature, and decomposition temperature in the present specification mean values measured by a differential scanning calorimetry (DSC) method based on JIS K7121.

(Second aspect)
In the second aspect of the surface processing step, the surface of the first member is heated to a temperature equal to or higher than the decomposition temperature of the resin (A).
As a heating means, a laser irradiation apparatus and an infrared heater are preferable. A laser irradiation apparatus is preferable in terms of heating a fine region. As the type of laser light, a gas laser such as a carbon dioxide laser or an excimer laser, a solid laser such as a YAG laser or a YVO ₄ laser, and a fiber laser can be used.
In this aspect, the surface temperature of the heated region of the surface of the first member is not less than the decomposition temperature of the resin (A) and may be not less than the decomposition temperature of the reinforcing fiber (B). The upper limit of the surface temperature is preferably Td + 200 ° C. or less, and more preferably Td + 100 ° C. or less, where Td ° C. is the higher of the decomposition temperature of the resin (A) or the decomposition temperature of the reinforcing fiber (B).
This aspect can process the surface of the first member in a shorter time than the first aspect, and is particularly suitable for exposing the reinforcing fibers (B).

(Common to the first and second aspects)
The first member before being heated in the surface processing step may be pre-shaped into a target shape or may be pre-shaped.
When the resin (A) is a thermosetting resin, the resin (A) may be already cured when heated, may be semi-cured, or may be uncured.

The heating time for heating the surface of the first member is such that an uneven shape is formed on the surface of the first member, as shown in FIGS. As shown in FIG. 2, the reinforcing fiber (B) is set to be exposed on the surface of the first member.
1 to 4 are cross-sectional views schematically showing a cross section perpendicular to the fiber direction of a first member obtained by impregnating a resin 2 with a reinforcing fiber sheet in which reinforcing fibers 1 that are continuous fibers are aligned in one direction. It is.
FIG. 1 shows the first member 3 before being heated in the surface processing step, FIG. 2 shows the first member 4 heated so that an uneven shape is formed on the surface, and FIG. The 1st member 5 heated until the reinforced fiber 1 was exposed is shown. FIG. 4 shows the first member 6 in which a regular uneven shape is formed by irradiating the surface with laser light.
5 to 7 are cross-sectional views of the first member in which the reinforcing fibers 11 that are discontinuous fibers are dispersed in the resin 12.
FIG. 5 shows the first member 7 before being heated in the surface processing step, FIG. 6 shows the first member 8 heated so that an uneven shape is formed on the surface, and FIG. The 1st member 9 heated until the reinforced fiber 11 was exposed is shown.

As illustrated in FIG. 2 or FIG. 4, on the surface of the first member on which irregularities (including irregularities due to exposure of reinforcing fibers) are formed by the surface processing, as shown in FIG. 2 or FIG. The difference from the bottom of the recess is defined as the maximum height (d _max ). The thickness direction means a direction perpendicular to the surface before being heated in the surface processing step.
In the molded article of the present invention, the maximum height (dmax) on the surface of the first member is preferably in the range of 1 to 45 μm. That is, it is preferable that the maximum height (dmax) in the cross section after being joined to the second member in the joining step described later is in the range of 1 to 45 μm.
When the maximum height (dmax) is 1 μm or more, an effect of improving the bonding strength due to the anchor effect is easily obtained. It can suppress that a space | gap part is formed in a junction part as it is 45 micrometers or less. The maximum height (dmax) is more preferably 5 to 40 μm, further preferably 10 to 30 μm.
In the surface processing step, with respect to the surface of the first member so that the maximum height (d _max ) in the molded body is within the above range in consideration of the change in the maximum height (d _max ) in the joining step. It is preferable to set heating conditions.

[Jointing process]
In the joining step, the material (D) containing the thermoplastic resin (C) is injection-molded on the surface (processed surface) of the first member whose surface is processed in the surface processing step.
For example, after a first member molded in advance is placed in a mold and a surface processing step is performed, the material (D) is injected onto the surface (processed surface) of the first member and the mold is injected into the mold. By molding the second member, a molded product in which the first member and the second member are joined is obtained.
Alternatively, the first member that is not molded into the final shape is placed in a mold, and after performing a surface processing step, the material (D1) is injected onto the surface (processed surface) of the first member. By molding the second member while shaping the first member in the mold, a molded product in which the first member and the second member are joined is obtained.

In the joining step, the temperature of the surface of the first member when the material (D) is injected onto the surface (processed surface) of the first member is equal to or higher than the melting point of the resin (A), or the resin (A ) Has a melting point or higher when it does not have a melting point.
The temperature of the surface of the first member is a temperature measured by a non-contact temperature sensor. An infrared thermography camera is exemplified as the non-contact temperature sensor. In the case of an infrared heater capable of heating a wide range as a heating means, the temperature of the heating surface is almost uniform, and the temperature is set as the surface temperature. In the case of a laser irradiation apparatus that heats a fine region as the heating means, the temperature of the heated fine region is defined as the surface temperature.
In the surface processing step, after the surface of the first member is processed by heating to the melting point of the resin (A) or higher than the glass transition point, the temperature of the surface is set to the melting point of the resin (A) or higher than the glass transition point. It is preferable to inject the material (D) in a state where the temperature is maintained.
Alternatively, when the surface temperature of the first member that has finished the surface processing step is lower than the melting point or glass transition point of the resin (A), the surface temperature is equal to or higher than the melting point of the resin (A) or glass. After reheating so as to be above the transition point, the material (D) is injected.

The upper limit of the surface temperature of the first member immediately before coming into contact with the material (D) is the decomposition temperature (Td) of the resin (A). The surface shape formed in the surface processing step is easily maintained, and the resin (A) and the resin in the material (D) are easily mixed, and the melting point (Tm ° C.) or higher and Tm + 200 ° C. or lower of the resin (A) is preferable. Tm + 30 ° C. or higher and Tm + 100 ° C. or lower are more preferable.
When the resin (A) does not have a melting point, the glass transition temperature (Tg ° C.) or higher and Tg + 200 ° C. or lower is preferable, and Tg + 30 ° C. or higher and Tg + 100 ° C. or lower is more preferable.
When the material (D) is injected onto the surface of the first member, the temperature of the material (D) (injection molding temperature) is higher than the surface temperature of the first member immediately before contacting the material (D). When it is high, the absolute value of the difference is preferably 100 ° C. or less, more preferably 70 ° C. or less, and further preferably 50 ° C. or less. When the temperature of the material (D) (injection molding temperature) is lower than the surface temperature of the first member just before contacting the material (D), the absolute value of the difference is preferably 100 ° C. or less, 70 ° C or less is more preferable, and 50 ° C or less is more preferable. As the absolute value of these differences is smaller, the material (D) is more easily filled in the uneven portion of the first member or the portion where the reinforcing fiber is exposed, and the void portion is less likely to occur in the joint portion. If a void portion is generated in the joint portion, it may be a cause of warping of a molded product made of the first member and the material (D).

In the molded body thus obtained, in addition to the anchor effect obtained by processing the surface of the first member, the material (D) is formed on the surface in a state where the surface temperature of the first member is high. The resin on the surface of the first member and the resin in the material (D) are mixed in a highly fluid state by injecting the second member to form the second member. The bonding strength with the member 2 is further improved.
The molded product produced by the method of the present invention has high mechanical properties and is suitably used for, for example, aircraft members, automobile members, sports equipment and the like.

Hereinafter, the present invention will be described in more detail using examples, but the present invention is not limited to these examples.
<Measurement method of maximum height (d _max )>
A sample polished so that a cross section along the thickness direction of the molded body was an observation surface was prepared and observed with a microscope. Measures the difference (maximum height) between the bottom of the deepest concave part and the top of the highest convex part among the irregularities on the surface of the first member in the field of view (interface between the first member and the second member) did. The field of view was changed, 30 measurements were taken, and the average value was taken as the maximum height (d _max ).
In addition, either the resin in the first member or the resin in the second member does not affect the physical properties as necessary so that the interface between the first member and the second member can be easily distinguished. You may color beforehand in the range.
<Tensile test method>
Using a tensile test apparatus (product name: Autograph AG-X, manufactured by Shimadzu Corporation), a tensile test was performed under the conditions of a distance between tabs of 120 mm and a test speed of 2 mm / min, and the value of the maximum test stress was recorded.
The maximum test stress (unit: kN) was divided by the bonding area to determine the value of tensile shear strength (unit: MPa) per mm ² .

<Raw materials>
Carbon fiber (1): manufactured by Mitsubishi Rayon Co., Ltd., product name: Pyrofil TR-50S15L, decomposition temperature 600 ° C., continuous fiber having an average fiber diameter of 7 μm.
Thermoplastic resin film (A1): (acid-modified polypropylene resin: manufactured by Mitsubishi Chemical, product name: Modic P958, melting point 165 ° C., decomposition temperature 400 ° C., basis weight: 36.4 g / m ² )
Fiber reinforced thermoplastic resin material (D1): Carbon fiber reinforced polypropylene resin, manufactured by Mitsubishi Rayon Co., Ltd., product name: Pyrofil pellet PP-C-30A. Melting point of resin: 170 ° C., decomposition temperature of carbon fiber: 600 ° C., average fiber diameter: 7 μm, weight average fiber length: 1.5 mm, fiber volume content (Vf) 18%.

(Production Example 1: Preparation of prepreg (1))
A continuous long reinforcing fiber sheet (unidirectional sheet) having a basis weight of 72.0 g / m ² by aligning the carbon fibers (1) in a flat shape so that the direction of the reinforcing fibers is one direction; did.
Both sides of this reinforcing fiber sheet are sandwiched between thermoplastic resin films (A1), and through a calender roll, the reinforcing fiber sheet is impregnated with a thermoplastic resin. The fiber volume content (Vf) is 33% and the thickness is 0.12 mm. Of prepreg (1) was obtained.
(Production Example 2: Creation of sheet-like material (first member))
17 square sheets obtained by cutting the prepreg (1) obtained in Production Example 1 into a size of 30 cm in length and 30 cm in width are laminated so that the fiber directions are the same, and press-molded, and the thickness is about 2 mm. The sheet-like material was obtained. The press molding was performed under the conditions of heating and pressing at a pressure of 0.3 MPa and 200 ° C. for 3 minutes, and then heating and pressing at a pressure of 1 MPa and 50 ° C. for 3 minutes.
(Production Example 3: Creation of sheet-like material (first member))
Five square sheets obtained by cutting the prepreg (1) obtained in Production Example 1 into a size of 30 cm in length and 30 cm in width are laminated so that the fiber directions of adjacent prepregs (1) are orthogonal to each other, and press-molded. A sheet-like material having a thickness of about 0.6 mm was obtained. The conditions for press molding were the same as in Production Example 2.

(Production Example 4: Preparation of prepreg (2))
6.5 g of carbon fiber (1) was cut (chopped) into a length of 5 mm. 10 L of water was placed in a rectangular parallelepiped stirring kettle equipped with a stirrer and having a side of 30 cm. While rotating the stirrer, the chopped carbon fiber was added and dispersed. The stirrer was stopped and water was discharged from the lower part of the stirring kettle to obtain a carbon fiber mat. It was dried for 3 hours with a vacuum heater maintained at 80 ° C. to obtain a nonwoven fabric having a square basis weight of 30 cm on one side and a weight of about 72 g / m ² . Similar to Production Example 1, both sides of this nonwoven fabric are sandwiched between thermoplastic resin films (A1), and the nonwoven fabric is impregnated with the thermoplastic resin through a calender roll. The fiber volume content (Vf) is 33% and the thickness is A prepreg (2) of 0.15 mm was obtained. Since the prepreg (2) contained voids, it was thicker than the prepreg (1).

(Production Example 5: Creation of sheet-like material (first member))
Seventeen square prepregs (2) each having a side of 30 cm obtained in Production Example 4 were laminated and press-molded to obtain a sheet-like material having a thickness of about 2 mm. The press molding was performed under the conditions of heating and pressing at a pressure of 0.5 MPa and 200 ° C. for 3 minutes, and then heating and pressing at a pressure of 1.5 MPa and 50 ° C. for 3 minutes. By making the pressure higher than in Production Example 2, voids in the prepreg were removed, and the sheet thickness was made the same as in Production Example 2.

The following test examples 1, 2, 5, 7, and 8 are examples using the production method of the present invention, and test examples 3, 4, 6, 9, and 10 are comparative test examples.
(Test Example 1)
A strip-shaped test piece (first member) having a length direction of 120 mm and a width direction of 25 mm was cut out with the fiber direction of the sheet-like material (thickness of about 2 mm) obtained in Production Example 2 as the length direction. As shown in FIG. 8, an infrared heater 22 (Nippon Gaishi Co., Ltd.) having a heater surface temperature of 500 ° C. in a heated region 21 a having a width direction of 25 mm × length direction of 12.5 mm at one end portion of one side of the test piece 21. (Product name: Infrastein heater) were opposed to each other and heated for 1 minute. In addition, the shielding board 23 was installed between the infrared heater 22 and the test piece 21 so that parts other than the to-be-heated area | region 21a might not be heated. Thus, the surface temperature of the heated region 21a of the test piece 21 was set to 200 ° C. As the surface temperature, an infrared thermography camera (manufactured by Avionics, product name: G120EX) was used. The surface of the heated region 21a was softened and became uneven as shown in FIG.
Subsequently, as shown in FIG. 9, while maintaining the surface temperature of the heated region 21a, the fiber reinforced thermoplastic resin material (D1) is immediately injected onto the heated region 21a using an injection molding machine. A strip-shaped member 24 (second member) having a direction of 120 mm and a width direction of 25 mm was formed. The temperature (injection molding temperature) of the fiber reinforced thermoplastic resin material (D1) at the time of injection molding was 230 ° C. Thus, as shown in FIG. 9, a molded body 25 is obtained in which the member 24 (second member) made of the fiber-reinforced thermoplastic resin material (D1) is bonded onto the heated region 21 a at one end of the test piece 21. It was.
About the obtained molded object 25, the tensile test was performed by said method and the tensile shear strength was calculated | required. Moreover, the maximum height of the 1st member in the joint surface of a 1st member and a 2nd member was measured by said method. These results and main production conditions are shown in Table 1 (hereinafter the same).

(Test Example 2)
In Test Example 1, the heating time for the heated region 21a of the test piece 21 (first member) was changed to 5 minutes, and the surface temperature was set to 220 ° C. Otherwise, the molded body was produced in the same manner as in Test Example 1.
(Test Example 3)
In Test Example 1, a molded body was produced in the same manner as in Test Example 1 except that the surface processing step was not performed on the test piece 21 (first member).
(Test Example 4)
In Test Example 1, after heating the heated region 21a of the test piece 21 (first member) and then cooling until the surface temperature reaches 25 ° C., a fiber reinforced thermoplastic resin material (on the heated region 21a) A molded body was manufactured in the same manner as in Test Example 1 except that the second member 24 was formed by injecting D1).

(Test Example 5)
In this example, the heated region 21a of the first member 21 is heated more than the decomposition of the resin.
That is, in Test Example 1, a laser irradiation apparatus (manufactured by SUNX, product name: LP-Z250, laser type: fiber laser, wavelength: 1060 nm) was used instead of the infrared heater. The heated region 21a of the test piece 21 (first member) is irradiated with laser light, and concave portions with a width of 30 μm and a depth of 20 μm are formed in a lattice shape at intervals of 150 μm, and regular irregularities are formed on the heated region. A shape was given. At this time, the surface temperature of the heated region 21a was 650 ° C. Then, after waiting until the temperature of the region reached 250 ° C., the fiber-reinforced thermoplastic resin material (D1) was injected onto the heated region 21a. Otherwise, the molded body was produced in the same manner as in Test Example 1.
In the joint surface between the first member and the second member of the obtained molded body, the concave portion formed in the first member was filled with the resin of the fiber reinforced thermoplastic resin material (D1).

(Test Example 6)
In Test Example 5, the heated region 21a of the test piece 21 (first member) was irradiated with laser light and heated, and then cooled to a surface temperature of 25 ° C., and then a fiber was formed on the heated region 21a. A molded body was produced in the same manner as in Test Example 5 except that the reinforced thermoplastic resin material (D1) was injected.

(Test Example 7)
In this example, the sheet-like material (thickness: about 2 mm) obtained in Production Example 5 was used and heated using an infrared heater.
A strip-shaped test piece (first member) having a length direction of 120 mm and a width direction of 25 mm was cut out from the sheet-like material (thickness: about 2 mm) obtained in Production Example 5. A molded body was produced in the same manner as in Test Example 1 except that this test piece was used.
In the surface processing step, the heated region 21a heated to the surface temperature of 200 ° C. was softened on the surface and became uneven as shown in FIG.

(Test Example 8)
In this example, the sheet-like material (thickness: about 2 mm) obtained in Production Example 5 was used and irradiated with laser light and heated.
A molded body was produced in the same manner as in Test Example 5 except that the same test piece as in Test Example 7 was used. In this example, the carbon fibers were exposed so as to partially protrude in the recesses formed in the surface processing step.
In the joint surface between the first member and the second member of the obtained molded body, the concave portion formed in the first member was filled with the resin of the fiber reinforced thermoplastic resin material (D1).

(Test Example 9)
A molded body was produced in the same manner as in Test Example 4 except that the same test piece as in Test Example 7 was used.
(Test Example 10)
A molded body was produced in the same manner as in Test Example 6 except that the same test piece as in Test Example 7 was used.

As shown in the results of Table 1, the surface processing step is performed by heating the surface of the first member, and the second member is injected in a state where the surface temperature of the first member is high to perform the bonding step. In Test Examples 1, 2, 5, 7, and 8 that were performed, molded articles with high bonding strength between the first member and the second member were obtained.
On the other hand, Test Example 3 in which the surface processing step was not performed, and although the surface processing step was performed, the test example in which the bonding process was performed by injecting the second member with the surface temperature of the first member being low. In 4 and 6, the bonding strength between the first member and the second member was inferior.

(Example 1: Production of molded body)
In this example, the molded body shown in FIG. 12 was manufactured through the surface processing step shown in FIG. 10 and the joining step shown in FIG.
A strip-shaped insert member 31 (first member) having a length direction of 40 cm and a width direction of 5 cm was cut out in advance from the sheet-like material (thickness: about 0.6 mm) obtained in Production Example 3. In addition, the fiber directions of the outermost layer and the outermost layer of the insert member 31 are the same, and this direction is the length direction. As shown in FIG. 10, the insert member 31 is disposed in the lower mold 32 of the molding die, and an infrared heater 33 (manufactured by NGK, product name: Infrastein heater) having a heater surface temperature of 600 ° C. is formed on the upper surface thereof. Opposed. The insert member 31 was heated by the infrared heater 33 for 3 minutes, and the surface temperature of the upper surface of the insert member 31 was set to 230 ° C.
Immediately after that, as shown in FIG. 11, the upper die 34 of the molding die is closed, and the fiber is fed from the resin supply path 35 provided in the upper die 34 into the space formed by the lower die 32 and the upper die 34. A reinforced thermoplastic resin material (D1) was injected. The injection molding temperature was 230 ° C., and the surface temperatures of the inner surfaces of the lower mold 32 and the upper mold 34 (molding mold temperature) were 50 ° C. Since the mold temperature is lower than the melting point of the resin in the fiber reinforced thermoplastic resin material (D1), the injected fiber reinforced thermoplastic resin material (D1) is cooled and solidified in the mold, and the second member. 36 was formed. 15 seconds after the injection of the fiber reinforced thermoplastic resin material (D1) was completed, the mold was opened, and the molded body shown in FIG. 12 was taken out.
The maximum height of the first member 31 at the joint surface between the insert member 31 (first member) and the second member 36 of the obtained molded body was 25 μm.

(Comparative Example 1)
In Example 1, when the heating time for the insert member 31 (first member) was changed to 30 seconds, the surface temperature of the upper surface of the insert member after heating was 130 ° C., and no irregularities were formed on the upper surface. It remained a smooth surface. Other than that was carried out similarly to Example 1, and manufactured the molded object.
The maximum height of the first member 31 at the joint surface between the insert member 31 (first member) and the second member 36 of the obtained molded body was zero.

(Example 2: Production of molded body)
In Example 1, an infrared heater was used, but in this example, the same laser irradiation device 37 as in Test Example 5 was used.
As shown in FIG. 13, the same insert member 31 as in Example 1 is placed in the lower mold 32 of the molding die, and the upper surface thereof is irradiated with laser light, and a recess having a width of 30 μm and a depth of 20 μm is formed in a lattice shape to 150 μm. Formed at intervals to give an uneven shape to the heated region. At this time, the surface temperature of the upper surface of the insert member 31 was 650 ° C. And it waited until the temperature of this area | region became 250 degreeC, and injected the fiber reinforced thermoplastic resin material (D1). Except that, a molded body was produced in the same manner as in Example 1.
The maximum height of the first member 31 at the joint surface between the insert member 31 (first member) and the second member 36 of the obtained molded body was 20 μm.

DESCRIPTION OF SYMBOLS 1,11 Reinforcing fiber 2,12 Resin 3, 4, 5, 6, 7, 8, 9 First member 21 Test piece (first member)
21a Heated area 22 Infrared heater 23 Shielding plate 24 Member (second member)
25 Molded body 31 Insert member (first member)
32 Lower mold 33 Infrared heater 34 Upper mold 35 Resin supply path 36 Second member 37 Laser irradiation device

Claims (6)

This is a method for producing a molded body in which a first member containing a resin (A) and a reinforcing fiber (B) and a second member made of a material (D) containing a thermoplastic resin (C) are joined. And
By processing the surface of the first member containing the resin (A) and the reinforcing fiber (B) to a temperature equal to or higher than the melting point of the resin (A) or higher than the glass transition point, the surface is processed into an uneven shape or the surface A surface processing step for performing processing to expose the reinforcing fiber (B) in
Manufacture of a molded body having a joining step of injection-molding a material (D) containing a thermoplastic resin (C) on the processed surface having a surface temperature equal to or higher than the melting point of the resin (A) or a glass transition point Method. This is a method for producing a molded body in which a first member containing a resin (A) and a reinforcing fiber (B) and a second member made of a material (D) containing a thermoplastic resin (C) are joined. And
By heating the surface of the first member containing the resin (A) and the reinforcing fiber (B) to a temperature equal to or higher than the decomposition temperature of the resin (A), the surface is processed into unevenness or the reinforcing fiber ( A surface processing step for performing processing to expose B);
Manufacture of a molded body having a joining step of injection-molding a material (D) containing a thermoplastic resin (C) on the processed surface having a surface temperature equal to or higher than the melting point of the resin (A) or a glass transition point Method.   The manufacturing method of the molded object of Claim 1 or 2 which heats the surface of the said 1st member with an infrared heater in the said surface treatment process.   The manufacturing method of the molded object of Claim 1 or 2 which irradiates a laser beam to the surface of the said 1st member in the said surface processing process.   The manufacturing method of the molded object as described in any one of Claims 1-4 with which the material (D) containing the said thermoplastic resin (C) contains a reinforced fiber further.   The molded object which is manufactured with the manufacturing method of the molded object as described in any one of Claims 1-5, and the maximum height in the surface of a 1st member is 1-45 micrometers.

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